1. Field of the Invention
The present invention relates to an optical fiber curvature sensor for measuring body motion and its adhesive method. More particularly, it relates to an optical fiber curvature sensor for measuring body motion and its adhesive method having an improved sensitivity for measuring body motions such as motions of fingers, arms, or legs, which is able to measure curving direction and curved degree of a subject simultaneously and applicable for subjects of which the surface areas are varying such as waist or shoulders, by adhering an optical fiber to a subject in curved-state.
2. Description of the Related Art
In the prior art related to an optical fiber curvature sensor for measuring body motion, a method for measuring motions of fingers, arms, or legs, which uses the fact that the characteristic of light through an optical fiber is changed when the optical fiber is bent, is disclosed in U.S. Pat. No. 4,542,291 (“Optical Flex Sensor”, patented Sep. 17, 1985, Thomas G. Zimmerman, VPL Research Inc.). In addition, a glove-type hand motion measuring device having various sensors is disclosed in U.S. Pat. No. 4,414,537 (“Digital Data Entry Glove Interface Device”, patented Nov. 8, 1983, Gary J. Grimes, Bell Telephone Lab. Inc.), and glove-type hand motion measuring devices having optical fiber curvature sensors have been developed thereafter (General Reality Company).
Additionally, an optical fiber curvature sensor is also used for measuring angles of arms or legs of which the articulations have one degree of freedom. Moreover, by laminating optical fibers having one degree of freedom, an optical fiber curvature sensor that can measure a 3-D shape in 3-D space has been developed (Measurand Inc.).
However, the optical fiber curvature sensors in the prior art described above are limited to measuring motions of subjects having small surface area variances such as fingers. Therefore, it is hardly applicable for measuring motions of subjects having large surface area variances such as waist or shoulders.
And, there exists another problem that the measuring devices for body motion in the prior art are very expensive because they are manufactured by using a high-price magnetic position sensor and/or a high-price image processing technique.